Yarn driven friction falsetwister

ABSTRACT

Process and apparatus are disclosed for sequentially drawing and imparting torque to a continuous filament synthetic yarn strand in a continuous process. The apparatus is adaptive to mounting on a conventional draw-twisting or draw-winding machine or for use on a winding apparatus without stretch drawing.

United States Patent [191 Rice [ June 18, 1974 YARN DRIVEN FRICTION FALSETWISTER [75] Inventor: Charles M. Rice, Candler, NC.

[73] Assignee: Akzona Incorporated, Ashville, NC.

[22] Filed: Aug. 8, 1973 [21] Appl. No.: 386,816

52 us. Cl 57/34 us, 57/555, 57/774, 57/157 TS 511 Int. Cl D02g 1/02, D02g 1/08 [58] Field of Search 57/34 HS, 157 TS, 55.5, 57/774, 157 s [56] References Cited UNITED STATES PATENTS 3,404,525 10/1968 Tompkins 57/157 TS UX 3,435,603 4/1969 Rice 57/34 HS 3,559,391 2/1971 Rice 57/34 HS 3,581,487 6/1971 Loomes 57/34 HS Primary Examiner-John Petrakes Attorney, Agent, or Firm-Francis W. Young; Tom R. Vestal ABSTRACT Process and apparatus are disclosed for sequentially drawing and imparting torque to a continuous filament synthetic yarn strand in a continuous process. The apparatus is adaptive to mounting on a conventional draw-twisting or draw-winding machine or for use on a winding apparatus without stretch drawing.

8 Claims, 3 Drawing Figures 1 YARN DRIVEN FRICTION FALSETWISTER BACKGROUND OF INVENTION Texturing of synthetic polymeric filaments is known. Further, it is known to draw and falsetwist yarn sequentially in a simultaneous process from US. Pat. No. 3,651,663 and British Pat. specification No. 777,625. It is also known to falsetwist yarn through the use of fluid jets from US. Pat. No. 3,279,164. More recently, the demand for higher process speeds has initiated what has become known as friction falsetwisting. British Pat. specification No. 1,255,317 is an example of this latter process.

The above disclosures contemplate the construction of an overall machine specifically designed for falsetwisting. or require extensive modifications and attachments to existing machinery. As such, the prior teachings present a deterrent to a manufacturer having substantial capital invested in conventional twisting or draw-twisting equipment.

THE PRESENT INVENTION The present invention is directed to modifying a yarn driven friction-falsetwisting device whose simplicity, compactness, and high speed twisting capability make it suitable for mounting on conventional twisting, winding, drawtwisting, or draw winding equipment. A further aim of the present invention is the manufacture of a stretch torque multifilament yarn in a simultaneous draw falsetwisting process. It is also an aim to adapt conventional twisting, winding, drawtwisting or drawwinding machinery to produce a uniform, high torque multifilament stretch hosiery yarn.

Adaption of conventional drawing machinery is accomplished herein by utilizing novel separator rollers associated with a conventional draw roller with a heat setting means interposed near the draw zone area. While the discussion herein shall be mainly directed to draw falsetwisting, conventional winding machinery having positive feed rolls to the winding area may also be adapted according to the teachings herein. The apparatus and process for use thereof are more fully understood by reference to the following Figures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view schematic of the invention on a conventional drawtwister apparatus.

FIG. 2 is a side view of the falsetwist section of FIG. 1.

FIG. 3 is a frontal view of an alternative embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS In FIGS. 1 and 2, an undrawn or partially drawn synthetic polymeric multifilament yarn is drawn from a supply source not shown and passed through a feed means, consisting of a driven feed roller 2 and nip roller 3, into a stretch drawing zone. In the drawing zone may be a draw pin 13 depending on the nature and drawing qualities of the particular synthetic polymeric yarn involved.

From the drawing zone, the now fully drawn yarn is passed around draw roller 4 and separator roller 12 located above the draw roller a number of times to establish sufficient tension in the drawing zone and to impart rotational energy to the separator roller for reasons discussed below. The yarn then passes through a twist arresting means 5 over a heater plate 6 located proximate and between the draw roller 4 and feed roller 2 and thereafter over a cylindrical heated pin 7 and between and through frictional disc surfaces 8 and 9. The frictional disc surface 9 is attached to and rotates with separator roller 12. The frictional disc surfaces 8a and 8b and cylindrical section 10 are attached to and rotate with separator roller 11 which is, in turn, rotated by wrapping several wraps of the yarn, as it leaves the disc surface 8b and transitional surface 8c pass onto cylindrical surface 8d, around separator roller 11 and draw roller 4. The separator roller 11 is thereby driven by passage of the yarn l. The yarn thereafter passes through guide 14 to a ring twister 15 where a producers twist of from one-fourth to one turn per inch may be added. Thereafter the yarn l is wound into a package 16. It is understood that the yarn may be wound directly in a package without twist also.

In FIG. 3, a drawn yarn 1 passes over a drive roller 4 and separator roller 12 through a number of wraps over the drive roller and separator roller. The yarn then proceeds through a twist stop device 5 and over a heating device 6a in the form of a J-shape. The shape of the heating device 6b directs the yarn into and between the rotating friction surfaces 8 and 9 in a similar manner to that shown in FIG. 1. Thereafter, the yarn is wrapped around separator roller 11 and drive roller 4 a sufficient number of wraps to drive the roller 11 and disc friction surface 8, before passing to a winding means not shown.

In the design of friction falsetwisting equipment for use on conventional drawtwisters and the like, several considerations must be kept in mind. The available space on the machine is limited, and therefore the twisting apparatus must be compact. It must be simple in that its cost should not be prohibitive nor its operation excessively complicated.

The yarn speeds on conventional drawtwisters range into several hundreds of meters per minute, and falsetwister apparatus adaptive to the conventional drawtwisting machinery must be able to insert sufficient twist at the conventional drawtwisting speeds. Yarn heating means must also be adequate to heat the yarn above its glass transition temperature and still be confined within the special limitations of an operating yarn processing point or the drawtwister without affecting. the adjacent operating points. Finally, falsetwisting equipment must be economical in operation and be capable of operating continuously for great lengths of time with little or no repair. The friction falsetwisting device of the present invention fulfills these enumerated conditions.

In the friction twister of the present invention, yarn twist is imparted through yarn contact with the rotating disc elements 8 and 9. Maximum twist capability is obtained when the yarn path between disc elements lies in a plane containing the axis of rotation of the discs. This condition is achieved, as shown in FIG. 2, in that the yarn path on surfaces 8a, 9 and 8b is substantially defined by planes containing the respective axes of idler roller 11 and 12 and which cross at the intersection point of the two rollers. Thus, in the present invenzone, the twist is removed from the yarn, leaving only the torque set in the false twist process. 1f high tension persists downstream of the zone, the falsetwist torque will be removed, as the yarn is'still in a semi-plastic state immediately downstream of the falsetwist zone.

In the present invention, the transition surface 80 is contoured so that the yarn path, which is at first parallel to the roller 11 axis at 8b and becomes more oblique to the axis, until just before the cylindrical section 8d of roller 11 the surface becomes substantially perpendicular to the roller 11 axis. A spherical shape has been found to be quite satisfactory. Yarn passing along the transitional surface is first pulled over the disc surfaces and given substantial twist, and thereafter is less subject to twisting forces and more to frictional pulling forces perpendicular to the roller axis. The transitional surface 80 acts as a heat transfer surface and the yarn becomes sufficiently cooled along the first part of section 80 to accept the higher tensions in the latter part of the transition section without removing the falsetwist torque set in the yarn. The transitional surface 80 also has the advantage of eliminating guides or other similar yarn contacting surfaces downstream of the falsetwist zone until the yarn has sufficiently cooled. Further, the similar rotation of overlapping disc surfaces 8a and 8b is effective in holding the yarn in proper position in the twisting zone so that no guides are needed.

Many of the elements in the present invention perform multiple functions. Roller 1 l twists the yarn, cools the yarn, guides it and spaces the drawing wraps on draw roller 4. Roller 2 assists in twisting the yarn, positions the yarn in the twisting zone, and spaces the driving wraps on roller 4. The multiple functions so performed by the elements greatly simplify and compact the falsetwist device, and increase its reliability, durability, and economy of operation.

Adequate twist effectiveness is attained by the use of chrome plated or ceramic coated steel; however, it is recognized in appropriate circumstances other materials may be used.

EXAMPLE 1 An undrawn nylon five filament yarn of 20 total denier was processed using the apparatus of FIG. 1 on a conventional drawtwister at a draw ratio of 2.66:1 The temperature of the heating surfaces 6 and 7 was maintained at 185 centigrade with the average r.p.m. of the friction surfaces being 10,000. The spindle speed of pirn 17 was 7,500 revolutions per minute. The textured yarn thereby produced had a final denier of 19.9 and tenacity of 4.5 grams per denier, an elongation of 31 percent, and had a uniform twist crimp equivalent to l42-l50 turns per inch. The yarn was subsequently knitted into a pantyhose which exhibited good fabric appearance and uniformity.

EXAMPLE 2 A 40/13 nylon multifilament yarn was processed using the apparatus of FIG. 3 on a conventional drawtwister at a draw ratio of 2.40:] The temperature of the heating device 6a was maintained at 185 centigrade. Spindle speed for windup was 7,600 rpm. The resultant yarn had a final denier of 40.6 with a tenacity of 3.7 grams per denier. Elongation of the yarn was 37 percent with a uniform twist equivalent of 100-110 turns per inch. The yarn performed satisfactorily during knitting into a pantyhose welt fabric and could be sewn without any problems. The resultant pantyhose welt was of good appearance and uniformity and had good stretch characteristics.

It can be appreciated the instant application and examples are set forth by way of illustration and not limitation. Various modifications may be made without departing from the spirit and scope of the invention herein.

What is claimed is:

l. A method of producing a falsetwist torque stretch yarn on a yarn winding apparatus having a winding means, a drive roller and first and second separator rollers spacially proximate and with substantially parallel axes to the drive roller, comprising the steps of:

a. wrapping yarn from a supply source around the drive roller and a cylindrical section of the first separator roller to impart rotational energy to the first separator roller:

b. wrapping the yarn around the drive roller and a cylindrical section of the second separator roller to impart rotational energy to the second separator roller in the same direction as said first separator roller; and

c. directing one wrap of yarn from the drive roller to a heating zone and thereafter axially between at least two friction disc sections on said second separator roller and at least one intermeshing friction disc section on said first separator roller and into substantial contact with and at an angle axially oblique to a transition surface between the disc section and cylindrical section of said second separator roller.

2. A method of draw falsetwisting synthetic polymeric yarn comprising the steps of stretch drawing said yarn and thereafter falsetwisting according to the method of claim 1.

3. The method of claim 2, further comprising the steps of winding the draw falsetwisted yarn into a package with substantially no twist.

4. The method of claim 2, further comprising adding a twist of from one-fourth to one turn per inch to the draw-falsetwisted yarn and thereafter winding into a package.

5. A drawtwister, having multiple yarn draw twisting positions, the improvement comprising, first and second yarn driven separator rollers mounted on the frame of said drawtwister spacially proximate and operable with a draw roller on the drawtwister, said first and second separator rollers having substantially parallel axes and said first roller having at least one disc shaped frictional yarn engaging surface, and said second separator roller having at least two disc shaped frictional yarn engaging surfaces, said yarn engaging surfaces on said first and second separator rollers intermeshing so that a yarn passing between the frictional engaging surfaces axial to the separator rollers will be deflected from a straight line path; yarn heating means attached to the drawtwister frame and interposed in a path of yam travel between said draw roller and said yarn engaging surfaces, and twist restricting means in the path of yarn travel upstream of said yarn heating means; the first and second idler rollers, yarn heating means, and twist restricting means being spacially confined to a single drawtwist operating point without interference with the operation of adjacent drawtwist points.

6. The drawtwister of claim 5 wherein said heating means comprises a substantially flat electrical resistance heated surface and a curved electrical resistance heated surface in sequence, said curved surface being located downstream in the yarn travel path of said substantially flat surface to deflect the yarn travel path onto said frictional engaging surfaces.

7. The drawtwister of claim 5 wherein said heating means comprises an electrical resistance heated surface, the upstream section of said heated surface being substantially flat and the downstream section being arcuate in shape along the path of yarn travel.

8. A method of producing a torque stretch yarn on a yarn winding apparatus having a winding means, a drive roller and first and second separator rollers spacially proximate and with substantially parallel axes to the drive roller, comprising the steps of:

a. wrapping yarn from a supply source around the drive roller and a cylindrical section of the first separator roller to impart rotational energy to the first separator roller;

b. wrapping the yarn around the drive roller and a cylindrical section of the second separator roller to impart rotational energy to the second separator roller in the same direction as saidflrst separator roller;

c. heating the yarn to at least the glass transition temperature; and

d. imparting a level of rotational energy to the yarn in a first zone, decreasing the level of rotational energy substantially uniformly while simultaneously increasing axial energy in said yarn in a second zone and thereafter winding the yarn a package. 

1. A method of producing a falsetwist torque stretch yarn on a yarn winding apparatus having a winding means, a drive roller and first and second separator rollers spacially proximate and with substantially parallel axes to the drive roller, comprising the steps of: a. wrapping yarn from a supply source around the drive roller and a cylindrical section of the first separator roller to impart rotational energy to the first separator roller: b. wraPping the yarn around the drive roller and a cylindrical section of the second separator roller to impart rotational energy to the second separator roller in the same direction as said first separator roller; and c. directing one wrap of yarn from the drive roller to a heating zone and thereafter axially between at least two friction disc sections on said second separator roller and at least one intermeshing friction disc section on said first separator roller and into substantial contact with and at an angle axially oblique to a transition surface between the disc section and cylindrical section of said second separator roller.
 2. A method of draw falsetwisting synthetic polymeric yarn comprising the steps of stretch drawing said yarn and thereafter falsetwisting according to the method of claim
 1. 3. The method of claim 2, further comprising the steps of winding the draw falsetwisted yarn into a package with substantially no twist.
 4. The method of claim 2, further comprising adding a twist of from one-fourth to one turn per inch to the draw-falsetwisted yarn and thereafter winding into a package.
 5. A drawtwister, having multiple yarn draw twisting positions, the improvement comprising, first and second yarn driven separator rollers mounted on the frame of said drawtwister spacially proximate and operable with a draw roller on the drawtwister, said first and second separator rollers having substantially parallel axes and said first roller having at least one disc shaped frictional yarn engaging surface, and said second separator roller having at least two disc shaped frictional yarn engaging surfaces, said yarn engaging surfaces on said first and second separator rollers intermeshing so that a yarn passing between the frictional engaging surfaces axial to the separator rollers will be deflected from a straight line path; yarn heating means attached to the drawtwister frame and interposed in a path of yarn travel between said draw roller and said yarn engaging surfaces, and twist restricting means in the path of yarn travel upstream of said yarn heating means; the first and second idler rollers, yarn heating means, and twist restricting means being spacially confined to a single drawtwist operating point without interference with the operation of adjacent drawtwist points.
 6. The drawtwister of claim 5 wherein said heating means comprises a substantially flat electrical resistance heated surface and a curved electrical resistance heated surface in sequence, said curved surface being located downstream in the yarn travel path of said substantially flat surface to deflect the yarn travel path onto said frictional engaging surfaces.
 7. The drawtwister of claim 5 wherein said heating means comprises an electrical resistance heated surface, the upstream section of said heated surface being substantially flat and the downstream section being arcuate in shape along the path of yarn travel.
 8. A method of producing a torque stretch yarn on a yarn winding apparatus having a winding means, a drive roller and first and second separator rollers spacially proximate and with substantially parallel axes to the drive roller, comprising the steps of: a. wrapping yarn from a supply source around the drive roller and a cylindrical section of the first separator roller to impart rotational energy to the first separator roller; b. wrapping the yarn around the drive roller and a cylindrical section of the second separator roller to impart rotational energy to the second separator roller in the same direction as said first separator roller; c. heating the yarn to at least the glass transition temperature; and d. imparting a level of rotational energy to the yarn in a first zone, decreasing the level of rotational energy substantially uniformly while simultaneously increasing axial energy in said yarn in a second zone and thereafter winding the yarn a package. 